1. Field of the Invention
This invention relates to file systems, and especially to trays, drawers, and other holders for filing individually removable microfiche and the like. More particularly it relates to means for releasably compressing the microfiche files in such holders for compact storage.
2. Prior Art
Typically, microfiche, microfilm aperture cards, computer floppy discs, and the like are stored in rigid open-top trays or drawers. Various systems have been devised for use with such trays and drawers to facilitate the manual insertion and removal of the individual information bearing units. U.S. Pat. Nos. 3,114,459 to Kersting and 3,347,393 to Frey are examples of such systems. Generally these systems incorporate means for applying force to compress some or all of the units into compact packs when they are not in use.
In some of these devices the compression means are adapted to be inclined at an angle to an imaginary vertical plane as well as being moveable longitudinally of the file tray or drawer to afford the user easy access to the individual units.
Some compressors of this type take the form of rigid end plates mounted for rotation about a horizontal axis extending transversely of the tray or drawer. Others employ one or more transversely mounted rigid tracks or railss adapted for movement longitudinally of the holder.
While these prior art compression mechanisms serve their intended purposes more or less satisfactorily, they are not without deficiencies. Some do not furnish sufficient compressive force to retain the individual units in place in the event the tray or drawer is accidentally upset. Some furnish adequate restraining force, but are subject to inadvertent release with potentially catastrophic results. Most of them require the use of two hands for their operation, and even with the use of both hands, generally afford the user little control over the amount of force exerted against the individual units. In the case of systems utilizing the compressing means for fanning or separating the individual units, this lack of precise control prevents the user from taking full advantage of the system's capability.
A number of filing systems provide means, such as embossments formed on segregators positioned between the individual units, for fanning or separating the units and enabling the user to examine their contents visually without removing them from the tray or drawer. U.S. Pat. No. 3,913,250 to Arthur T. Spees, and my U.S. Pat. No. 4,231,175 are illustrative of systems of this type. Such systems likewise generally include means for compressing the information bearing units, and, not surprisingly, these suffer from similar deficiences.
In an effort to design an improved compression mechanism for my patented file system, I developed and tested a compressor assembly comprising two rigid rectangular plates joined at their respective lower and upper edges by means of a piano hinge and maintained in planar alignment by means of a torsion spring mounted to the hinge pin. Mounting means secured to the side edges of the upper plate near its lower end permitted the "split" compressor to be mounted to a pair of axially aligned rods attached to the inside of the side walls of a file drawer for rotation about an imaginary horizontal axis transverse to the drawer.
The mounting means were designed to clamp to the supporting rods when the compressor was in a vertical position, and to permit the entire assembly to slide longitudinally of the drawer on the rods when the compressor was rotated out of the vertical plane.
In principle, sliding the compressor toward, say, a set of microfiche standing at one end of the drawer would bring the bottom edge of the lower plate into contact with the lower portion of the closest microfiche. Advancing the compressor further would urge the lower edges of the microfiche together.
When the force required to overcome the collective resistance offered by the individual units exceeded the torque exerted by the torsion spring, the lower plate would rotate about the axis of the piano hinge until the face of the lower plate abutted the face of the closest fiche. Still further advancement of the compressor would cause the lower plate to urge the fiche successively into vertical alignment and then into compression.
At that point the lower plate of the compressor would be aligned vertically as well, and continued advancement of the compressor would cause the upper plate to rotate about the piano hinge axis into vertical alignment with the lower plate, thereby applying maximum compressive force to the compacted microfiche and simultaneously locking the compressor assembly in place.
In actuality, however, the hinged compressor proved to have certain drawbacks. Notably, for reasons not entirely clear, but probably associated with the nature of torsion springs, the action of the assembly was neither as fluid or as precisely controllable as had been anticipated.
In an attempt to overcome these deficiencies I developed and tested a compressor consisting of a thin flexible resilient sheet of plastic material fastened by means of rivets to a rigid backing plate which extended across the upper two thirds of the sheet and served as a stiffener. As in the earlier assembly, self-locking mounting means secured to the rigid plate near its lower end supported the compressor on a pair of rails and provided for both longitudinal movement and rotation of the compressor.
While this construction was an improvement over the earlier one, it still suffered, albeit to a lesser extent, from the previously mentioned deficiencies encountered with the split compressor. Apparently, the resilient strip joined to the rigid plate with a portion of the strip extending beyond the plate was the functional equivalent of a pair of rigid plates joined by a hinge and retained by a torsion spring.
Based on the foregoing experience I have now constructed a compressor which avoids the problems encountered with the earlier designs. With this new compressor, the invention disclosed here represents a novel compression system that can be adapted advantageously to virtually any microfiche holder and that avoids the deficiencies mentioned earlier which are inherent in the prior art file systems.
One object of the invention is to provide compression means capable of applying sufficient force to the contents of the tray or drawer to retain the contents in the tray or drawer even if it should be upset.
Another object is to provide a compression mechanism for file trays and drawers which can be operated readily with one hand.
Yet another object is to provide compression means which allow the user to control the force applied to the individual units smoothly and with precision regardless of the number of units or their location in the tray or drawer.
Still another object is to provide compression means which will not interfere with the operation of prior art fanning and separating systems of the type previously mentioned.
Other objects and features of the invention and its advantage over the prior art will become apparent to the reader from the following detailed description of several of its preferred embodiments as illustrated in the accompanying set of drawings.